If you live in a high rf zone / big city, you will probably find you need it on VHF HI public safety band and maybe VHF air 109-136 mhz, WITH AN OUTDOOR ANTENNA. With the duck antenna you probably won't need att. But WHEN you want to hook it up to an outdoor....
Do this:
Leave it on global, then try it ON first, and when a vhf frequency comes up, hit the att button to see what happens. I'll bet some of the weaker tx's stop at that instant, when you turn attenuation off. This will verify that you NEED att with these frequencies. Try it on UHF too, though you probably won't need it there. Once you know what frequencies need it (probably vhf hi - if yo u live in a high rf zone), then just program it into those frequencies, and use NORMAL attenuation. You don't want to be attenuation UHF, and especially don't want to attenuate 800 mhz frequencies.
